Wed Jun 17 16:19:00 EST 1992

We had a slight problem with ExoIII deletions and disappearing DNA as well.
The problem in our case was that according to the procedure the ExonucleaseIII
needed to be heat denatured at 70C before the S1 nuclease step and if you are
not careful to let the DNA cool SLOWLY after the denaturation then the S1 will
chew through any unannealed DNA.  We repeated the procedure many times before
realizing this problem.  We weren't using the kit but you might pay close
attention to how you're carrying out this step of the procedure.
Melissa Melan				Internet:(mmelan at
Wellesley College
Department of Biological Sciences
Wellesley, MA  02181

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